The present invention relates to a gas injector having a gas injection nozzle for forming a reactive deposition film, which is used in manufacture of semiconductor circuit substrates such as ICs and LSIs, and to a gas injection direction adjusting method using such a gas injector.
Conventionally known is a semiconductor manufacturing device having the structure as shown in FIG. 13 for forming a reactive deposition film on wafers 51 as semiconductor substrates. The semiconductor manufacturing device as shown in FIG. 13 includes a quartz bell jar 52 of a hollow vessel, a susceptor 53, and a pair of reaction gas injection nozzles 54. The susceptor 53 is a wafer holder in the form of a polygonal pillar which is detachably stored in and coaxial with the quartz bell jar 52.
The reaction gas injection nozzles 54 are provided on the upper portion of the quartz bell jar 52. The reaction gas injection nozzles 54 are provided to inject reaction gas, for example, such as hydrogen gas or silan gas while controlling pressure (e.g., at 25 PSI (pounds per square inch)) and flow rate. The injected reaction gas circulates inside the quartz bell jar 52 to allow a reactive deposition film to grow on the surface of the wafers 51 and flows towards a vent 52a provided on the lower portion of the quartz bell jar 52. The susceptor 53 is arranged to also rotate about the axis. This allows the reactive deposition film to have an even thickness with respect to the wafers 51 held on the susceptor 53.
In the semiconductor manufacturing device having the foregoing arrangement, in the event where jet flows of the reaction gas injected from the pair of reaction gas injection nozzles 54 are not aligned in direction or angle, the density of the gas flows inside the quartz bell jar 52 will not be uniform, and the reactive deposition film formed on the wafers 51 comes to have uneven film thickness. In order to solve this problem, the direction or angle of the reaction gas injection nozzles 54 needs to be adjusted.
The following explains how the reaction gas injection nozzles 54 were fastened and adjusted conventionally based on FIG. 14(a) through FIG. 14(c).
First, the fastening procedure will be explained referring to FIG. 14(a). A nozzle case 61 is fixed on a fastening screw 52c formed on each inner wall of a pair of gas supply openings 52b which are provided on the upper portion of the quartz bell jar 52. To the nozzle case 61 are attached a nozzle 62 and a nozzle retainer 64. The nozzle 62 is temporarily fixed in place with a nozzle fixing screw 64a. 
Here, a spherical portion 62a at the rear end of the nozzle 62 is held between a ring-shaped front end of the nozzle case 61 and the front end of the nozzle retainer 64 and is slidable. This allows the front end of the nozzle 62 to be adjusted at any angle in the horizontal and vertical directions by the sliding spherical portion 62a. 
The following describes how the injection angle is adjusted in the reaction gas injection nozzle 54. First, as shown in FIG. 13, a direction indicator board 65 is placed at a predetermined position in the injection direction of the reaction gas at the upper portion of the quartz bell jar 52. Then, a nozzle direction indicator rod 66 (FIG. 14(b)) is inserted into a gas injection opening 62b of the nozzle 62 (FIG. 14(a)). Thereafter, the tip of the nozzle direction indicator rod 66 is adjusted to point 0 (target direction) on the center of the direction indicator board 65 by changing the direction of the nozzle 62. The nozzle fixing screw 64a is then tightened from the side of a gas supply joint section 68 on the side of the base end to fix the adjusted direction or angle of the nozzle 62.
Here, the spherical portion 62a of the nozzle 62 is fixed by the front end of the nozzle case 61 and the front end of the nozzle retainer 64 by the pressure of the screwed nozzle fixing screw 64a. As a result, the spherical portion 62a becomes unslidable. Thereafter, the nozzle direction indicator rod 66 is removed from the nozzle 62, and the direction indicator board 65 is removed from the quartz bell jar 52.
Then, as shown in FIG. 14(c), the gas supply joint section 68 is connected to the nozzle case 61 so as to seal the quartz bell jar 52. Afterwards, the connected portion of the nozzle case 61 and the gas supply joint section 68 is checked for gas leakage while reducing pressure inside the quartz bell jar 52 using a vacuum pump. Then, the gas and wafers 51 are fed to start forming the reactive deposition film on the wafers 51.
However, the foregoing prior art has the problem of low productivity in formation of the reactive deposition film on the wafers 51.
That is, in the foregoing prior art, the nozzle 62 is fixed after adjusting the direction or angle of the nozzle 62 by once loosening the nozzle fixing screw 64a, which necessitates tightening the nozzle fixing screw 64a from the gas supply side.
Therefore, the foregoing prior art required unfastening and fastening of the gas supply joint section 68 before and after adjustment, respectively. That is, there were additional operations of fastening the nozzle 62, attaching or detaching the gas supply joint section 68 to adjust the nozzle direction, and checking for gas leakage at the connected portion of the nozzle case 61 and the gas supply joint section 68. As a result, productivity suffered.
It is an object of the present invention to provide a gas injector which can improve productivity without requiring the conventionally required additional operations, and to provide an adjusting method thereof.
In order to achieve this object, a gas injector in accordance with the present invention includes: a nozzle main body having on its front end portion a nozzle for injecting gas; and a nozzle main body supporting section for supporting the nozzle main body, wherein the nozzle main body includes first and second members, and displacing means for changing relative positions of the first and second members, and fixed state/unfixed state of the nozzle main body with respect to the nozzle main body supporting section is switched by a change in relative positions of the first and second members by the displacing means, and injection direction of the gas from the nozzle is changed by changing a disposition direction of the nozzle main body in an unfixed state.
In this arrangement, the nozzle main body having the nozzle on its front end portion is supported by the nozzle main body supporting section. Further, the fixed state/unfixed state of the nozzle main body with respect to the nozzle main body supporting section is switched by changing relative positions of the first and second members by the displacing means. By the nozzle main body switched to the unfixed state, the disposition direction of the nozzle main body is changed, thereby changing the gas injection direction.
Thus, the gas injection direction can easily be changed by switching the nozzle main body to the unfixed state, and the adjusted gas injection direction can be fixed by switching the nozzle main body to the fixed state after the adjustment.
Switching of the nozzle main body to the fixed state/unfixed state is carried out by the displacing means of the nozzle main body.
Thus, compared with, for example, the arrangement of the foregoing prior art which requires adjusting the nozzle fixing screw and the like from the gas supply side, the gas injection direction can be adjusted more easily and quickly.
Further, it is possible to omit additional operations, such as checking for gas leakage, which were required when adjusting the nozzle fixing screw and the like from the gas supply side, thus improving productivity.
Further, in order to achieve the foregoing object, a gas injection direction adjusting method in accordance with the present invention is for a gas injector which includes: a nozzle main body having on its front end portion a nozzle for injecting gas; and a nozzle main body supporting section for supporting the nozzle main body, wherein the nozzle main body includes first and second members, and displacing means for changing relative positions of the first and second members, and fixed state/unfixed state of the nozzle main body with respect to the nozzle main body supporting section is switched by a change in relative positions of the first and second members by the displacing means, and the method includes the steps of: inserting an adjusting rod from a gas injection opening of the nozzle so as to adjust a gas injection direction of the nozzle by a tip of the adjusting rod; and fixing the nozzle main body on the nozzle main body supporting section by changing relative positions of the first and second members.
In this method, the gas injection direction is adjusted and set by the tip of the adjusting rod which is inserted in the nozzle to change the disposition direction of the nozzle main body after switching the nozzle main body to the unfixed state. The nozzle main body is fixed after adjustment so as to fix the adjusted gas injection direction.
As a result, the nozzle main body can be fixed on the nozzle main body supporting section by the operation from the nozzle side through, for example, visual confirmation of the tip of the adjusting rod pointing a predetermined direction.
Thus, compared with the conventional fixing by tightening from the gas supply side, conventionally required additional operations can be omitted with the foregoing method. Further, the gas injection direction can be adjusted and set from the nozzle side through confirmation from this side, thus performing fixing securely and quickly.
For a fuller understanding of the nature and advantages of the invention, reference should be made to the ensuing detailed description taken in conjunction with the accompanying drawings.